Near field scanning microscopy is a technique for analyzing objects by means of a light beam which is directed through a very small aperture. The width of the aperture is made substantially smaller than the wavelength of the light (e.g., .lambda./40), and the object to be studied is held in the near field of the aperture. The near field begins at the surface of the material in which the aperture is formed and extends outward a distance equal to about one-half of the width of the aperture. During scanning it is very important that the aperture be maintained at a constant distance from the sample.
A known type of NSOM is described in U.S. Pat. No. 4,917,462 to Lewis et al. An aperture probe is made in the form of a tapered metal-coated glass pipette. The pipette is formed from a glass tube drawn down to a fine tip and then coated with a metallic layer. An aperture is formed in the metallic layer at the tip. The manufacture of such a probe is a relatively expensive, time consuming process that does not lend itself to batch fabrication techniques. These drawbacks are overcome in an NSOM according to this invention.